fix:refactor c implementation

---
type: pre_push_report
description: Results of running various checks prior to pushing changes.
report:
  - task: run_javascript_examples
    status: na
  - task: run_c_examples
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  - task: run_cpp_examples
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---

Author: jalajk3004

lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/examples/c/Makefile

@@ -57,7 +57,8 @@ CFLAGS ?= \
 	-std=c99 \
 	-O3 \
 	-Wall \
-	-pedantic
+	-pedantic \
+	-v
 
 # Determine whether to generate position independent code ([1][1], [2][2]).
 #
@@ -84,7 +85,6 @@ LIBPATH := -L$(PWD)/lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/
 # List of C targets:
 c_targets := example.out
 
-
 # RULES #
 
 #/

lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/include/stdlib/stats/base/dists/signrank/quantile.h

@@ -16,8 +16,8 @@
 * limitations under the License.
 */
 
-#ifndef STDLIB_BASES_DISTS_SIGNRANK_QUANTILE_H
-#define STDLIB_BASES_DISTS_SIGNRANK_QUANTILE_H
+#ifndef STDLIB_STATS_BASE_DISTS_SIGNRANK_QUANTILE_H
+#define STDLIB_STATS_BASE_DISTS_SIGNRANK_QUANTILE_H
 
 /**
  * Evaluates the quantile function for the Wilcoxon signed rank test statistic.
@@ -28,4 +28,4 @@
  */
 double stdlib_base_dists_signrank_quantile(double p, int n);
 
-#endif // !STDLIB_BASES_DISTS_SIGNRANK_QUANTILE_H
+#endif // !STDLIB_STATS_BASE_DISTS_SIGNRANK_QUANTILE_H

lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/lib/native.js

@@ -20,9 +20,7 @@
 
 // MODULES //
 
-var addon = require( './../src/addon.node' );
-console.log(addon);
-
+var addon = require( './../src/addon' );
 
 
 // MAIN //
@@ -48,7 +46,10 @@ console.log(addon);
 * // returns NaN
 */
 function quantile( p, n ) {
-	return addon( p, n );
+	if (typeof p !== 'number' || typeof n !== 'number' || n <= 0 || p < 0 || p > 1) {
+        return NaN; 
+    }
+    return addon(p, n);
 }
 
 

lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/src/Makefile

@@ -45,6 +45,19 @@ endif
 endif
 endif
 
+# Compiler and flags
+CC = gcc
+CFLAGS = -fPIC -shared
+
+# Source files
+SRC = addon.c
+
+# Target shared object
+TARGET = addon.node
+
+# Build rule
+$(TARGET): $(SRC)
+	$(CC) $(CFLAGS) -o $@ $^ -I/path/to/stdlib/include -L/path/to/stdlib/lib -lstdc++
 
 # RULES #
 

lib/node_modules/@stdlib/stats/base/dists/signrank/quantile/src/main.c

@@ -17,35 +17,34 @@
 */
 
 #include "stdlib/stats/base/dists/signrank/quantile.h"
-#include <stdio.h>
+#include <math.h>
 
 /**
-* Evaluates the quantile function for the Wilcoxon signed rank test statistic with `n` observations.
+* Evaluates the quantile function for the Wilcoxon signed-rank test statistic with `n` observations.
 *
 * @param p    input probability
 * @param n    number of observations
-* @return     evaluated quantile
+* @return     evaluated quantile or NaN if inputs are invalid
 *
 * @example
 * double y = stdlib_base_dists_signrank_quantile( 0.5, 5 );
 * // returns 11
 */
-int main() {
-    double probabilities[] = {0.1, 0.25, 0.5, 0.75, 0.9};
-    int sample_sizes[] = {3, 5, 7, 10};
-
-    printf("Quantile Function for Wilcoxon Signed Rank Test\n");
-    printf("------------------------------------------------\n");
+double stdlib_base_dists_signrank_quantile(double p, int n) {
+    if (isnan(p) || p < 0.0 || p > 1.0 || n <= 0) {
+        return NAN; 
+    }
 
-    for (int i = 0; i < sizeof(sample_sizes) / sizeof(sample_sizes[0]); i++) {
-        int n = sample_sizes[i];
-        printf("\nSample size (n): %d\n", n);
-        for (int j = 0; j < sizeof(probabilities) / sizeof(probabilities[0]); j++) {
-            double p = probabilities[j];
-            double result = stdlib_base_dists_signrank_quantile(p, n);
-            printf("P: %.2f -> Quantile: %.4f\n", p, result);
+    int max_rank_sum = (n * (n + 1)) / 2;
+    double cumulative_prob = 0.0;
+    for (int rank_sum = 0; rank_sum <= max_rank_sum; rank_sum++) {
+        double pmf = 0.0;
+        cumulative_prob += pmf;
+        if (cumulative_prob >= p) {
+            return (double)rank_sum;
         }
     }
 
-    return 0;
+    
+    return NAN;
 }